JoshClose/CsvHelper — pull request #198 by gwely (2013-10-24 15:45:43+00:00)
Title: added prependEquals param to CsvWriter.WriteField

prependEquals == true when a field is a number. By prepending an equals
sign to the field, Excel does not remove leading and trailing zeros.
Fixed a single formatting test, too.

Not sure if the code is OK with you, feel free to change it.